Engine starter



Dec. 25, 1934.

' J. F. G. PETIT ENGINE STARTER Filed March 14, 1933 2 Sheets-Sheet l Q Dec. 25, 1934.

J. F. G. PETIT ENGINE STARTER 2 Sheets-Sheet; 2

Patented Dec. 25, 1934 l UNITED STATES PATENT OFFICE ENGINE STARTER Jean Francois Gabriel Petit, Paris, France, as-

signor to Etablissements Labinal, Saint-Ouen (Seine), France Application March 14, 1933, Serial No. 660,744

In France December 12, 1932 8 Claims. (Cl. ISO-38) The invention relates to engine starters com,- Consequently, even should the operator allow prising an electric motor and an electro-mechanithe starting switch to remain unduly closed for cal device connected with the motor and it has too long a time, the starting pinion, once thrown for its object to devise a starter adapted to sebackward by the engine gear after the engine cure the correct engagement of the driving pinhas been started, will in no case incidentally re- 5 ion with the toothed gear of the engine to be turn into engagement with said engine gear. started; another object of the invention is to pro- Further characteristics of the invention will be vide an arrangement in which the full power set forth in the following description, with refof the electric motor is applied when the pinion erence to the accompanying drawings, which and engine gear are in meshing engagement; 8. show, by way of example, a preferred embodi- 10 further object of the invention is to provide for ment of the invention. the automatic release of the driving pinion from Fig. l is an axial section of the starter end the engine gear when the engine is started; a adjacent the starting pinion. still further object of the invention is to provide Fig. 2 is an end view of the starter, partly in a starter in which the arrangement of the parts section and with the front bearing removed. 15 and of the electric circuits are such that, when Fig. 3 is a plan view corresponding to Fig. 2, the driving pinion is released from the engine with the main frame removed. gear after the engine has been started, it will Fig. 4 is a diagram of the circuit. be impossible for the pinion to re-engage the Figs. 5 and 6 are semi-diagrammatical views engine gear, unless the starting switch has been of the automatic switch, respectively in eleva- 20 opened and again closed. tion and in plan view.

Accord ng h i v n on, the circuit of the With reference to Fig. l, the armature of the armature and of the series .field winding of the electric motor 1 is keyed to a hollow shaft 2, starting motor is controlled by an automatic mounted in a rear bearing on the side next the switch shunted by a resistance, said switch becollector (not shown) and in a front bearing 3, 25 ing operated by a device which participates in which is centered and secured in the frame 4 of the lengthwise motion of the pinion which is the motor. Within hollow shaft 2 is mounted 2. adapted to engage the engine gear, in such mancoaxial shaft 5, journalled at its outer end in a nor that the starting motor is set running at support 6 of suitable shape, axially secured to slow speed when the starting switch is closed, frame 4, extending beyond bearing 3 with refer- 30 and is only supplied at full load, (through the ence to motor 1, series field windings) after a sufiicient ,displac Outwardly with reference to support 6, shaft ment of the driving pinion, corresponding to the 5 carries a starting pinion '7 adapted to engage proper meshing engagement of the pinion with the toothed gear of the engine to be started.

5 the engine gear. Shaft 5 is formed with an enlargement 8 having According to another feature of the invention, a conical internal surface adapted to engage the the closing of said automatic switch is adapted conical surface of a nut 9, co-operating with a to cause the full energizing of a relay adapted screw 10, keyed to shaft 2. A spring 11, hearing to maintain said switch in its .closed position, upon support 6 and upon a suitable cup-shaped 40 until the operator opens the starting switch. member 12, urges the parts just described in the 40 Another feature of the invention resides in that position shown in the drawings. Member 12 is an electro-magnetic winding or solenoid, 0011- held against rotation with reference to support 6 nected in series with the armature and with the by a key 13, secured to said support. series field windingsof the motor (and which may In the axial movement of the parts toward serve the purpose of the above-mentioned rethe left (Fig. 1) member 12 meets a hook at the 45 sistance), is associated with a device for braking end of a rod 14, thus moving the latter and actuthe rotation of the starting pinion, thus promotating an automatic switch 23, controlling motor ing the lengthwise displacement of said pinion 1, as will be further set forth. during the first step of the starting operation, Within frame 4 is coaxially mounted an elecsaid solenoid being then short-circuited by the tro-magnetic unit which is held between the 50 automatic switch when the starter operates at bearings 6 and 3, and comprises three solenoids full load, whereby said solenoid cannot cause 17,1"! and 18. Said electromagnets are clamped again braking of the rotation of the starting between an outer end-plate 15 and an inner pinion as long as the relay for the automatic stamped piece 16. The movable cores of the 5 Switch remainsenergized. 1 two solenoids 17, 17 are secured to a rhombusshaped plate 20, which, under the action of the solenoids, is adapted to engage the end of nut 9, thus exerting thereon an axial pressure in the direction of the axial motion of pinion '7 towards the engine gear to be actuated. Springs 21 normally keep plate 20 away from nut 9 when solenoids 17, 17 are not energized.

The core 22 of solenoid 18 is secured to a copper contact member 23, adapted to bridge two contact-pieces 24-24 under the action of rod 14, operated by member 12, as above explained. Contact member 23 is held against pieces 24, 24 when solenoid 18 is energized, as will be further set forth. A spring 25 urges member 23 away from contact-pieces 2424 As shown in Figs. and 6, contact member 23 preferably comprises a short switch-knife 41 and a long contact arm 40, and contact-piece 24" is provided with a switch-jaw whose two branches 42-43 are made of a material having a relatively high electric resistance and co-operate with the knife 41. When rod 14 is moved outwardly by member 12, contact member 23, owing to the friction of the knife in the switch-jaw, will first pivot until arm 40 engages contact piece 24, and closes the circuit; at this instant however the branches 4243, inserted in series in the circuit, offer a great resistance to the current. As rod 14 still moves to the left, contact member 23 pivots in the opposite direction about the point of contact between arm 40 and contact piece 24, and knife 41 slides between branches 42-43, towards contact-piece 24 thus reducing progressively the resistance inserted in the circuit. This provides for the gradual closing of the circuit, and prevents all sparking which would damage the con tact parts.

In the wiring diagram of Fig. 4, 1 is the armature of the electric motor, 2525 are the motor brushes, 26 the series field winding, and 27 the shunt field winding; 28 is a storage battery for supplying the starting current; 29 is a starting switch for closing the motor circuit; 30 represents the earth or one terminal of the circuits; 31 is the engine gear belonging to the engine to be started.

Like in Figs. 1 to 3, 7 denotes the starting pinion, 1'7 the braking solenoids, 18 the relay of the automatic switch, 20 the braking plate for the nut, and 23 the copper contact member which is adapted to bridge contact pieces 2424**.

The operation of the starter is as follows. When starting switch 29 is closed, the battery supplies current to the armature 1 and the shunt field windings 27 of the motor, and also to solenoids 17. The starting motor is thus set running at a slow speed, due to the high resistance of the windings 17, which are in series with the armature and the series field windings of the motor. Motor shaft 2 rotates screw 10, which tends in turn to rotate nut 9, but the windings of the solenoids 17 are now energized, and their cores move inwardly within the solenoids, thus shifting plate 20, against the action of springs 21. Plate 20 meets the rear end of nut 9, thus counteracting its rotation, while exerting thereon a pressure in the direction corresponding to the displacement of pinion 7. Nut 9 will be moved along screw 10, together with shaft 5 and pinion 7, against the action of spring 11. Pinion '7 thus engages the engine gear 31 (Fig. 4).

If the teeth of pinion '7 are not in the proper position relatively to the teeth of the engine gear when the meshing engagement is to take place, nut 9, which is stopped in its axial motion, will turn slightly until it engages smoothly the engine gear, thus dispensing with the usual lateral clearance which is provided in the toothing of engine gears on the side next the starting pinion for permitting easy engagement.

When pinion 7 has engaged the engine gear, which is still at rest, its rotation is prevented by said engine gear, and the unit consisting of pinion 7, shaft 5 and nut 9 will still move to the left, although the action of plate 20 on nut 9 has now ceased, since the cores of the solenoids 1'7 have reached the ends of their strokes. Before pinion '7 has reached the end of its stroke to the left, and before nut 9 has abutted against the end shoulder of screw 10, stamped piece 12 engages rod 14, thus moving contact member 23 until it bridges contact-pieces 2424 against the action of spring 25. A calibrated spring 19 yields to any further movement of rod 14 as soon as disc 23 bearsupon contact pieces 24, 24.

Due to the contact between contact pieces 24, 24 and contact member 23, the motor circuit is directly earthed through the wire 44, the windings of the solenoids 17 are short-circuited, and the winding of the relay 18 is fully energized due to the smaller resistance of wire 44 than solenoid 17. Hence, the battery supplies the motor with the maximum current which can be absorbed thereby. The operation of relay 18 assures the proper contact between member 23 and contactpieces 2424 The power supplied by motor 1 is now suflicient to operate the engine to be started at the proper speed. The engine is set running, and its speed will immediately exceed the starting speed, so that the engine gear will now drive the starter pinion together with nut 9, at a greater speed than starter shaft 2 and screw 10, whereby nut 9 is moved backward along said screw. Spring 11 aids in this motion by its expansion. Nut 9 is thus returned to its initial position, pinion 7 re-engaging the outer end of bearing 6.

If at this time the operator has duly opened switch 29, the motor 1 will now stop, and the starting operation is completed. But, if, for any reason, switch 29 remains closed, the motor will simply continue to rotate, without any contact between the starting pinion and the engine gear, since solenoids 17 are short-circuited, whereby plate 20, which is held by springs 21, will be unable to brake nut 9; thus, the latter will turn together with screw 10, without moving along this screw. In order that pinion 7 may move towards the engine gear, switch 29 must be first opened, and then closed. This will afford a most reliable operation, as compared with the known systems, in which it may happen that, when the starting motor is set running, the starting pinion again enters in meshing engagement with the engine gear, should the operator fail to open the starting switch.

It should be observed that the conical parts of member 8 and nut 9 constitute a torque-limiting device yielding to abnormal stresses.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

1. In a starting unit, an electric motor, a starting member, a screw connection between said member and the shaft of said motor, and electromagnetic means in the circuit of said motor for pressing on said member in the direction of axial movement thereof due to said screw connection, and for simultaneously braking rotation of said member.

2. In a starting unit, a rotary and axially moviii able pinion, an electric motor, a supply circuit for said motor, an automatic switch controlling the supply of said motor, a manually operated switch in said circuit, a screw connection between said pinion and the shaft of said motor, electromagnetic means embodying a winding of relatively great resistance shunting said automatic switch for braking rotation of said pinion and causing axial displacement thereof, a relay, said automatic switch controlling the circuit of said relay, means for connecting said switch with the armature of said relay, whereby closure of said automatic switch causes energizing of said relay, which in turn keeps said automatic switch in its closed position, and means responsive to axial movement of said pinion for controlling said automatic switch.

3. In a starting unit, an electric motor, a screw on the motor shaft, a starting pinion, a nut connected with said pinion and engaging said screw, braking means adapted to press on said nut in the direction of the starting axial movement thereof and electromagnetic means in the circuit of said motor for actuating said braking means.

4. In a starting unit, an electric motor, a screw on the motor shaft, a starting pinion, a nut connected with said pinion and engaging said screw, a braking plate adapted to engage the inner end of said nut, a number of solenoids in the circuit of said motor, the movable cores of said solenoids being attached to said plate.

5. In a starting unit, an electric motor, a screw on the motor shaft, a starting pinion, a nut engaging said screw, braking means adapted to brake said nut, electromagnetic means in the circuit of said motor for actuating said braking means, a shaft for said pinion, a clutch element on said shaft, a mating clutch element on said nut, and resilient means for engaging said clutch elements and opposing axial starting movement of said nut and pinion.

6. A starting unit as claimed in claim 2, wherein said switch comprises a fixed contact stud, a fixed contact jaw of relatively great resistivity, and a pivotal contact member adapted to bridge said stud and jaw and connected with said axial movement responsive means, said movable contact member having a long arm opposite said stud and a knife frictionally engaging said jaw.

7. In a starting unit as claimed in claim 3, stroke limiting means for said braking means, adapted to relieve said nut upon engagement of said pinion with the engine to be started.

8. A starting unit as claimed in claim 2, wherein said latter means comprise an axially movable and non-rotatable member operatively connected with said rotary and axially movable member, a rod connected with the movable contact of said automatic switch, a stop on said rod, engageable by said axially movable and non-rotatable member for actuating said movable contact after a predetermined axial stroke of said last-mentioned member, and resilient means between said rod and said movable contact.

JEAN FRANCOIS GABRIEL PETIT. 

